A popular form of sport competition involving off-road motorcycles is the Enduro race. An Enduro race challenges the skill of the motorcycle rider by providing a rough terrain course having one or more segments of established distance which must be covered at a constant speed or speeds. The object of the race is to maintain the set or chosen speed over the distance of the course. Due to terrain limitations and for other reasons, it is customary that the course is divided into segments of differing difficulty, each segment having a commensurate speed which is to be maintained.
In order to judge the accuracy with which individual competition riders maintain the desired speed, unannounced checkpoints, manned by racing officals, are established along the course in order to give multiple points at which the time and distance of each rider can be measured. This time and distance in turn indicate whether the rider is ahead of or behind the chosen speed.
Each checkpoint, therefore, provides a score for each rider passing it, and the overall competition results are determined by combining the individual checkpoint scores.
It is customary in Enduro racing that the riders are sequenced into "rows" and that each row, that is, a set of 4 to 5 riders, is sequenced for a start time exactly one minute after the preceeding row and one minute before the row immediately subsequent. Thus, an Enduro race has a plurality of individual one-minute starts, each start being one row of riders. This spacing is intended to ease the official's task in timing and measuring riders.
It is customary, for convenience of monitoring the progress of each rider, that unannounced checkpoints will be positioned at one or more points, selected so that a whole tenth of a mile race distance corresponds exactly to a whole minute of time, timing from the beginning of the race. It should be obvious that with this method of checking, every rider should arrive at the checkpoint at exactly that minute, plus or minus zero seconds representing his relative start position on row; thus the error of timing of an individual rider can be determined from the number of seconds the rider is early or late with respect to his individual minute through the specific checkpoint.
In order to prevent the obvious expedient of simply stopping prior to entering the checkpoint if one is early, the rule is that the rider must continue to proceed; if, at any time a rider stops in sight of a checkpoint, his stop is timed as though passage has occurred. Thus, the individual riders require a method of continuously monitoring their progress.
Enduro racing on motorcycles involves the relatively high speed operation of a motorcycle over rough, back country terrain. The successful operation of the motorcycle under controlled conditions requires the full attention of the rider.